Removable liner for guns



June 30, 1925.

P. MALAVAL ET AL REMOVABLE LINER FOR GUNS Filed May 6, 1922 I nf Ve n tara M By A A )aM/M tm; @@w; ma* Attorneys Patented alune 30, 1925.

n U'Nir :einnnn MALAVAL AND annie PAUL EUGNE raeunninn, or ranas, FRANCE.'

REMOVABLE LINEE FORY GUNS.

Application filed' May 6,

To all whom it may concern:

Be itr known that we, PIERRE MALAVAL and REN PAUL EUGNE PAQUELIER, citizens of the Republic` or" France, residents of Paris, France, have invented new and useful Improvement-s ink Removable Liners for Guns, which invention is fully set forth in the following specification.

This invention has for its object a process for renovating worn gun barrels and modifications in the internal arrangements of gun barrels by lining the bore of the gun barrel.

In gun barrels as constructed hitherto the inner tube which constitutes the liner of the gun immediately surrounding Athebore of the gun, is assembled with the outer elements by transverse tightening, that is to say, before the assembling, the external .diameter of the liner isv greater than the internal diameter of the hooping or reinforcing element.

When the bore is worn, it is necessary to remove this liner which is -fairly thick, either by destroying same in the lathe, or by heating the outside of the gun barrel and cooling the liner;this process however is never successful in the case of gun barrels of large and medium calibres.

Afterwards, if it is desired to renovate the gun barrel, the elements mustvbe assembled afresh with a new liner. This operation requires approximately nine months in the case of a large gun barrel with the methods commonly in use.

In gun barrels as hitherto constructed'in which there. is a transverse compression as above dened, this compression isa positive stresjs,'that is to say, the difference between the external diameter of thevinner tube andthe internal diameter of the hooping or reinforcing element is a positive quantity.

The process` forming the subject vmatter ofthe present invention consists in constituting4 the liner of the gun barrel by means of a thin lining tube which is assembled with the encircling elements of the gun barrel without any compressive lstress, that is -to say, at the time of assembling the ele-` Y ments together, there exists a diametral playbetweenethe thin lining tube and the encircling elements.

Further, the lining tubeis made of a metal having a suitable elastic limit such that the said play whichis absorbed at the instant of firing the gun, reappears in the 1922. serial no.' 558,994.

state of rest (that is after the tiring 'of the gun)- and subsists indefinitely;

The desired elastic limit is determined in the 'following manner Let j be the play (or negative compression), 11 the outside radius of the thin lining tube, R0 the inside radius of the gun barrel, R, the outside radius of the gun barrel.

At thel dierence between the tensile stress which exists in the outer layer of thethin lining tube during the state of rest, and the tiring tensile stress Ain thesame outer layer produced by the firing 'of the gun. l

A25 the dierence between ythe tensile stress which exists in the inner layer of the bored\ gun barrel, during the state of rest, and the liring tensile stress in the same inner layer.

P0 the pressure in the bore,

P1 the pressure in the radial play space,

E the elastic limit of the metal,

M the modulus of elasticity and the interior of the thin lining. v I

Tn the firing tensile stress7 (that is, the tension caused by the explosion of the gun charge) in the tube.

Then the compressive stress is represented by:

On the other hand, we have these twoy fun-v damental relations, namely:

These .ive equations with the five .unknown quantities: Y

At, at', P To and E give n.

` In order to'withstand .any deformation and*v any longitudinal shifting o f' the thin lining tube as well as any torsion of' thel latter .duef to the eect of. the frictionor1 the projectile and the action of the rifling grooves etc., the thin lining tube and the `given an initial setnby,

bore of the gun barrel are provided with any suitable projections, shoulders, nibs, keys, etc., arranged as far as' possibleV in such a manner as not to interfere with the removal of the thin lining tube. a Y

The accompanying drawings illustrate by way of example a constructional formof a thin lining tube and a lined gun barrel ac? cordingto this present invention.

Figure 1 is an elevation of the thin lining tube; and l Figure 25K-is 'a Vlongitudinal section of a gun barrel fitted with the thin lining tube shown in Figure 1. A n

1 isa thin lining tube made of gun metal of high elastic limit, and 2 are shoulders situated about one metre apart along the outside of the said thin lining tube in the region corresponding to the rifiing of the bore. These shoulders are designedto resist ,thei permanent elongation .of the thin lining tube due to the effect of the firing of the gun, and also overcome any tendency to force the thin lining tube towards the muzdale Vend ofthe gun barrel. Y

The thin lining tube is also provided with tongues 3 or sectors intended to resist theV permanent torsion which tends to be produced by the passageof the projectile.

` 4 is a ring or sleeve forreinforcing the breech; it is screwed cold upon the ygun barrelv 5- and hasa constant, tendency to force the thin lining tube towards the muzzle end of the gun barrel.

6 isfthe play (or negative compression) provided between the thinjlining tube and the gun barrel 5. I

The improved process is applicable to gun barrels made in one piece whether they are hydraulic compression or not; alsoto ordinary hooped or reinforced gun barrels; and'likewise to gun barrels made of more than one piece having initialset by compression; in a word, the process is applicable to all gun barrels. l 1

A modification' offthe'process consists in reducing or even in doing away altogether with the play after the liner has been placed in position, by longitudinalcompression between the breech ring or sleeve and the shoulders hereinbefore referred to.

In all cases the improved process has the following advantages f 1. Instead of requiring many months for retubing or relining a gun barrel in a special factory furnished with lathes, bol ing machines, tube-fitting trenches, and hoisting appliances, this operation can be done in a few minutes at proving grounds at any spot; on board-ship .for small and medium calibres; in a harbourfor warships; in an artillery park of an army division for field guns, and in case of necessity in the battery posltion for entrenched guns. The

improved process requires only a few minutes, as a matter of fact it is merely necessary t unscrew the breech ring or screw 4 thathas been put on cold. y

2. Worn gun Vbarrels can be renovated at small cost.

`3. Old gun barrels can be reconstructed internally for receiving the improved thin lining tube according to this invention, and thus be converted into the latest model. Y r Y,

l4. The amount of steelwhich is necessary for relining gun barrels according tot this invention, is very small sothat gun-,makers need no longer fear a deliciency in the available quantity of'such steelin time of war.

5. The power of old gun barrels can be increased because i initial stress or set by hydraulic compression before being relined. Y i

6. yIf the type of powder thatis. used at presentV should become replaced by amore powerful type, old gun barrels may still continue to be used owing to the employment of the improved lining tube.

VLA gun comprising, in combination, a barrel and an elastic metal lining tube'within the bore of the barrel, the diameter of the boreof said barrel and the external diameter of the tube being so proportioned that the barrel confines said tube within itselastic limits under the stress of fire while leaving play between the tube and barrel when relieved of such stress, whereby said tube is easily removable. i f

.ZjA'gun comprising, in combination, a barrel, an elastic metaly lining tube within the bore of the'barrel, the diameters'of the bore thebarrel Vand the exterior 'of the tube beingso proportioned that the barrel confines theltube within its 'elastic' limits underthe 'stress of lire while leaving playV confines the tube f within 'its elasticY limitsV under Ythe stress 4of,k iire while. leaving play between the tube' andmbarrel when relieved ofy such stress, whereby the tube is rendered easily removable, and means restraining said tube from circumferential movement within' the bore.A

4. A gun barrel, an` elastic Ymetal lining tube within the bore of the barrel, the diameters'of the boreY of the barrel andthe exterior of the tube being so proportionedthat the barrel new gun barrels of they vcan be given an;

comprising," in combination, a

confines the tube within its elastic limits under the stress of re while leaving play between the tube and barrel when relieved of such stress, whereby the tube is rendered easily removable, and a reenforcing sleeve around the breech end of the barrel and confining the tube within said barrel.

5. A gun comprising, in combination, a barrel, and an elastic metal lining tube within the bore of the barrel, said tube being provided with a plurality of exteriorly formed annular shoulders of difierent diameters engaging corresponding shoulders within the bore of the barrel, the diameter of the bore of said barrel and the external diameter of the tube throughout their lengths being so proportioned that the barrel confines said tube within its elastic limits under the stress of tire while leaving play between the tube and the barrel when relieved of such stress, whereby said tube is rendered easily removable.

6. A gun comprising, in combination, a barrel having a plurality of shoulders formed interiorly thereof, and an elastic metal lining tube having shoulders formed eXteriorly thereof for engagement with said inst-named shoulders when the liner is associated with said barrel, whereby the movement of the liner toward the muzzle of the gun is prevented, and a reenforcing .sleeve surrounding the exterior of the breech end of the barrel and engaging said lining tube, the external diameter of the tube and the diameter of the bore of the barrel being so proportioned that the barrel contines said tube within its elastic limits under the stress of re while leaving play between the tube and barrel when relieved of such stress whereby said tube is easily removed.

7. A liner for a gun comprising a metal tube provided with a plurality of eXteriorly formed annular shoulders of dierent diameters, and a plurality of teeth formed one adjacent each of said shoulders, said shoulders being concentric and laterally spaced apart.

In testimony whereof we afix our signatures.

P11-:RRE MALAVAL. REN PAUL EUGNE PAQUELIER. 

